Liquid Gold poppers at Europe’s largest manufacturer of the product in Huddersfield.
Photograph: Christopher Thomond for the Guardian

The UK’s poppers manufacturers should be allowed to operate while the government reviews the product’s legality, the former deputy prime minister Nick Clegg has said.

The government’s psychoactive substances bill will come into force on 6 April, making poppers illegal in the UK. In response to calls to exempt the product from the bill in January, the government announced a review of the ban, which is expected to report before the summer recess in July, leaving a window of around three months in which UK poppers manufacturers risk going bust.

Poppers is the name given to the chemicals alkyl nitrites, which, when sniffed, give the user a short, sharp head rush. The substance was first circulated as an angina medicine before emerging as a party drug on the gay scene in the 1970s.

Poppers are particularly, though not exclusively, used by gay and bisexual men to enhance sexual pleasure, as they relax the muscles and make it easier to have anal sex. They are sold for about £5 a bottle in most sex shops and some cornershops and are available for anybody over the age of 16 to buy.

Yorkshire is the poppers capital of Europe, with the largest and second largest manufacturers based in Huddersfield and Leeds respectively. Between them, the two companies sold 2m 10ml bottles of the product last year.

“Poppers have been around for decades,” said Clegg, who is leading a campaign to persuade EU leaders to back global reform of drugs laws. “The evidence shows they don’t pose any great risk to health, and that’s why they have never been banned before.”

He told the Guardian: “Frankly they could have been made exempt from the new act without the need for a review, but the government didn’t want to admit they had got it wrong. While there is a review ongoing, of course the legitimate businesses that produce poppers should be allowed to continue to operate.”

John Addy, who runs Europe’s largest poppers manufacturer, Liquid Gold Aromas in Huddersfield, has mounted a campaign to maintain the legality of the product he has been selling for 35 years. He has complained that, to date, he has received no communication from the government about the ban.

Addy wants the government to agree to a new test case to determine whether poppers fall within the definition described under the psychoactive substances bill and for the industry to be allowed to carry on functioning legally until an official decision has been reached.

A report by the home affairs select committee in October, ahead of the bill’s passage in January, concluded that the party drug should not be banned since, according to the Advisory Council for the Misuse of Drugs, its use was “not seen to be capable of having harmful effects sufficient to constitute a societal problem”.

The Home Office claims that poppers have been mentioned on 20 death certificates since 1993, and that banning the product would save lives. Addy disputes those figures and insists there is no evidence that you can die from using poppers.

“If it had been killing people, we would have known about it. And I would never sell something that I thought was harming people,” he recently told the Guardian. “I have been selling this product for 35 years and it was used as a medicine for 100 years before that.”

The national drug education service Frank lists poppers as being potentially dangerous for anyone with heart problems or anaemia. A study in the Lancet, published in 2014, also claimed to have established a “clear cause–effect relationship” between the use of poppers and eyesight damage.

The gay rights charity Stonewall has warned that a ban on poppers would criminalise the lifestyles of many gay and bisexual men and has called on the government to speed up its review of the product.

“It is clear to us that allowing a full ban to go ahead in April will cause confusion, and more importantly could put gay and bi men’s health at serious risk,” said the charity. “People who use poppers will be forced to turn to illegal suppliers who could supply poppers containing unknown harmful substances or indeed more harmful illegal drugs. This is not acceptable and puts gay and bi men at risk.”

Unlike previous UK drugs legislation, which specifically names banned drugs, the bill applies a blanket ban to any substance intended for human consumption that is capable of producing “a psychoactive effect”. This meant a string of exemptions had to be included for alcohol, tobacco, coffee, tea, food and other medicinal products.